Question

What is the role of the sarcoplasmic reticulum in muscle contraction?

Answer 1

Sarcoplasmic reticulum:

It is a complex network of the specialized smooth endoplasmic reticulum that is important in transmitting the electrical impulse as well as in the storage of calcium ions.

Role of sarcoplasmic reticulum in muscle contraction:

1. Sarcoplasmic reticulum stores calcium ions and releases them into the sarcoplasm for the generation of action potential during muscle contraction.
2. The binding of calcium ions to troponin removes the masking of active sites of myosin present on actin filaments.
3. When an action potential occurs, the signal reaches the SR and causes the release of the large stores of Ca²⁺ ions.
4. These calcium ions will initiate the start of the contraction of muscle cells.
5. When the contraction is no longer needed, the SR will actively pump Ca²⁺ back into the SR lumen for future use.